<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

    <style>
        /*
        -moz- Firefox
        -webkit- chrome safari
        -ms- IE
        -o- Opear
        用于区分不同浏览器的内核，当CSS属性是实验性质的时候，可以加浏览器私有前缀，让对应浏览器兼容*/


        .one{
            width:800px;
            height:300px;
            background:pink;
            display: flex;
            /*display:flex;*/
            display: -o-flex;
            display: -webkit-flex;
            display: -moz-flex;
            display:-ms-flex;
            justify-content: space-between;
            -o-justify-content:space-between;
            -webkit-justify-content:space-between;
            -moz-justify-content:space-between;
            -ms-justify-content:space-between;
            -webkit-align-items: center;
            -ms-align-items: center;
            -o-align-items: center;
            -moz-align-items: center;
            align-items: center;
        }
        .one>div{
            width:200px;
            height:200px;
            background:tomato;
        }


    </style>


</head>
<body>

<div class="one">
    <div>1</div>
    <div>2</div>
    <div>3</div>
</div>


</body>
</html>